The invention relates to the patterning of circular knitting machines.
The use of striping boxes to increase the versatility of patterns which can be knit on a circular knitting machine is very well known. Conventionally, each striping box is comprised of a plurality of yarn-carrying fingers or other members, for example four such fingers. Often, each feeding station of the circular knitting machine will be provided with a striping box.
Depending upon which one of the four yarn-carrying fingers of each striping box is in dropped or activated state, a different one of four different yarns will be fed to needles travelling past the striping box. By controlling the activation and deactivation of the yarn-carrying fingers at the feeding stations of the machine in accordance with a preselected pattern, it is possible to knit patterns which could not otherwise be produced.
The most common use of striping boxes is in the formation of club stripes, i.e., horizontal stripes having a height, expressed in courses, equal to a multiple of the number of courses which the knitting machine could otherwise produce per needle cylinder rotation if its feeding stations were not provided with striping boxes.
Conventionally, the yarn-carrying fingers of the striping box are activated and deactivated under the control of a control drum provided with removably mounted finger-activating jacks. The jacks may have the form of flat members which are inserted into holding recesses or alternatively pins which are screwed or pushed into holding sockets of the drum. In the latter case, the control drum is provided with a plurality of such holding portions arranged in tracks, each track being associated with one yarn-carrying finger, the holding portions furthermore being arranged in rows, each row corresponding to a predetermined rotation of the needle cylinder.
The control drum is indexed in synchronism with needle cylinder rotation in a manner which is very well known. Usually a control chain is provided having high and low links. The control chain is driven in synchronism with the rotation of the needle cylinder, one link per cylinder rotation. A high link on the control chain causes the control drum to be indexed by one step, whereas a low link on the control chain fails to index the control drum; i.e., the control drum idles. When the control drum is indexed one step in this manner, one control jack or pin will move out of the finger-activating position and another will move into the finger-activating position. If the second control member (jack or pin) is in the same track as the one which it replaces, there will be no change in the activation of the yarn-carrying fingers and the same yarn will continue to be fed; if the second control member is in a track different from the one in which was located the pin which it replaces, then there will be a change in the activation of the yarn-carrying fingers and a different yarn (for example, yarn of a different color) will be fed.
For reasons well known in the art, it is often desired to form a knitted cloth using thick yarns, to give bulk to the cloth or to create any of a variety of special effects. When the feeding station is provided with a striping box, it is conventional practice to thread one of the yarn-carrying fingers of the striping box with the thick yarn. When the thick yarn is to be employed, the finger on which it is threaded is activated. Usually, the thick yarn is too thick to be actually knit and is instead utilized merely as the float for any of a variety of types of lay-in cloth.
A significant drawback of threading one of the thick lay-in yarns onto a yarn-carrying finger of a striping box is that the versatility of the striping box becomes reduced. If the striping box has only four yarn-carrying fingers, then one fourth of its capacity is relegated to the carrying of a yarn which can be laid in only and not knit, or which can at most be knit to the extent of one or a few stitches. This decrease of capacity becomes most apparent, for example, when the pattern to be knit consists of a succession of differently colored and/or patterned horizontal stripes, with only one or a few of the stripes requiring the thick lay-in yarn. Likewise, if two successive stripes of lay-in cloth are to be produced utilizing a thick lay-in yarn of different color for each of the stripes, then two of the four yarn-carrying fingers must be set aside for carrying the two thick lay-in yarns, one for the one stripe and the other for the second. This means that only the two remaining yarn-carrying fingers are available for the carrying of yarn which can actually be knit. This clearly limits very greatly the variety of stripe colors which can be produced.